Blind stitch sewing machine



June 3, 1941.

G. STEVENSON BLIND STITCH SEWING MACHINE Filed Feb. 17, 1939 2 Sheets-Sheet l INVENTOR A ORNEY June 3, 1941;,

G. STEVENSON BLIND STITCH SEWING MACHINE Filed Feb. 17. 1939 2 Sheets-Shegt 2 INVENTOR A ORNEY Patented June 3, i941 PATENT OFFICE BLIND s'rrron SEWEENG MACHINE Geoffrey Stevenson, Brookline, Mass, assignor to Lewis Invisible StitchiMachine 00., St. Louis, Mo., a corporation of Maine 9 Claims.

The invention herein disclosed relates to a blind stitch sewing machine and more particularly to an arrangement of mechanism in such machines for forming a node of material in the path of the needle.

In blind stitch sewing machines, there is commonly provided a plate, termed a presser foot, having an opening therethrough. A needle is caused to reciprocate across the opening through the presser foot and node-forming means are provided for projecting a node of material through the opening in the presser foot and into the path of the needle. These node-formin means and the operating mechanism therefor have been constructed in various forms depending upon the type of machine and the operations to be performed on the machine.

An object of this invention is to provide a machine of this type that is suitable for performing many blind stitch operations. Another object of theinvention is to provide a machine of this type having a node-forming mechanism suitable for performing the skip-stitch operation used in sewing dress bottoms, and in which machine the node-forming, means and the operating mechanism therefor are simple of construction and comparatively inexpensive to manufacture.

The foregoing objects, certain other objects and advantages that will hereinafter appear, are realized in accordance with this invention by ing an opening therethrough, and a needle that is mounted for movement across the opening in the presser foot. Two relatively movable nodeforming elements are provided, each operative to independently project a node of the material operated upon through the opening in the presser foot and into the path of the needle. Operating mechanism effects the operation of the nodeforming elements to move them into and out of Fig. 7 is a similar elevation illustrating the node-forming elements in a different relative position; and

Fig. 8 is a partial isometric of a modified form of the machine.

Only those parts of a chain-stitch, blind-stitch sewing machine necessary to illustrate the invention are shown in the drawings and described below in detail. The general construction of the machine has been illustrated in order to properly and operatively disclose the relation of the novel -mechanism which in such a machine constitutes an embodiment of the invention. In general, as illustrated, a chain-stitch, blind-stitch sewing machine includes a frame, stitch-forming mechanism, node-forming mechanism, and operating mechanism for effecting the timed, cyclic operation of the stitch and node-forming mechanisms.

The'frame of the machine illustrated in Figs.

1 to 7 of the drawings includes (Figs. 1 and 2) a base I, a standard 2 extending from the forward side of the base (the side facing the operator), a hollow vertical standard 3 at the other or rear end of the base, a lateral arm 4 extending from the upper end of the vertical standard '3, and a forwardly projecting arm 5 secured on the end of the lateral arm 4. All of the operating mechanism of the sewing machine, with the exception of part of the operating means of the providing in a sewing machine apresser foot hav- 1 node-forming mechanism, is te on t e frame. Part of the operating means for the node-forming means and the node-forming mechanism are mounted on a work table 6 that is pivotally mounted on the standard 2 through a pivot pin 1.

The stitch-forming mechanism (Figs. 1, 2 and 3) includes a curved needle 8 and a looper 9. The needle 8 is secured in a needle bar It) (Figs. 1 and 2) which is fastened on the extended end of an oscillatory shaft ll journaled in the forwardly extending arm 5. The looper 9 is fastened to the end of a looper bar I2 that is actuated by mechanism l3 in such a manner that it picks up the loopof' thread formed at the beginning of the return stroke of the needle and presentsthe loop so that the needle passes through the loop on the next stroke of the needle. A top feed dog [4 (Fig; 3) effects linear movement of cloth throughthe machine, the feeding action taking place While the needle is withdrawn.

The shaft ll is oscillated, the looper operating mechanism actuated and the feed dog operated in timed relation to efiect a series of stitches in cloth passing through the machine. This operation is effected through a main shaft i journalled in the laterally extending, frame arm 4. The end of the main shaft extends through the arm 4 at the standard 3. A combined hand wheel and grooved pulley i5 is mounted on the extended end of the main shaft which is driven by means of a belt (not shown), driving through the pulley.

In its reciprocations, the needle 8 passes across an opening lla (Figs. 3 and 4) through a presser foot IT. The presser foot is secured by brackets i8 and i9, extending therefrom to the forward end of the frame arm 5, and has formed therein a groove ll'b for guiding the needle in a fixed path across the opening lia. A resilient cloth retaining clamp is mounted on the presser foot and overlies a portion of the opening through the presser foot, just in front of the path of the needle. An edge guide 2! may also be secured to the presser foot and serve as a guide for an edge of the cloth passing through the machine.

The work table is as stated pivotally mounted on the standard 2 at the forward end of the base of the machine through the pivot pin 1. The

Work table includes (Figs. 1 and 2) an extension 22 that extends beneath the presser foot I! and the work table is resiliently urged towards the presser foot. Positioning means are provided for determining the position of the work table with respect to the presser foot and a control knob 23 is provided on the standard 3 for adjusting the position of the work table. Work supports or platens 24 (Fig. 2) are mounted on the extended end of the Work table, one on each side of the opening through the presser foot. These platens are resiliently urged against the under side of the presser foot and serve to clamp the work against the presser foot. The top feed dog :4 has a compound motion by virtue of which at the start of its feeding action it presses down the work supporting platens and thus relieves the clamping force's, leaving the cloth free to move toward the rear of the machine with the feed dog.

All of the foregoing construction and operating mechanism, inter-related as described are common and well known in blind-stitch, chainstitch sewing machines. Such mechanism, together with mechanism for effecting the cyclic operation of the several parts in timed relation, is illustrated, by way of example, in Patent No. 1,905,391, issued April 25, 1933.

The node-forming mechanism (Figs. 4 to 7) for projecting a node of the material operated upon through the opening in the presser foot and into the path of the needle includes two relatively movable, independently operable node-forming one ratio so that the jack shaft isrotated half as a node of the material operated upon through the opening in the presser foot and into the path of the needle to an ineffective position in which it is withdrawn from directly beneath the path of th needle. Oscillation of the shaft 21 (Figs. 1 and 2) is effected through an eccentric mounted on the main shaft l5 that is surrounded by an eccentric strap 3m forming a part of a curved lever 31. The lever 3| extends down through the standard 3 and the base I to a point beneath the work table 6. A connecting rod 32 pivotally secured to the end of the lever 3| and secured to the shaft 21, transforms the movement of the lever into oscillatory movement of the shaft 21. The disk 25 is thus oscillated in a one to one relation with the needle, the arrangement of the eccentric being such that the disk moves up to the effective position as the cloth is fed and while the needle is withdrawn, remains in the effective position during the forward, penetrating stroke of the needle and. is retracted on the return stroke of the needle.

The disk 26 is oscillated in a two to one relation with respect to the needle. Oscillation of the sleeve 36 is effected through a jack shaft 33 journaled in the side wallof thevertical-standard 3. This shaft is connected to the main shaft l5 through gears 34 and 35, The gear 34 is mounted on the main shaft and the gear 35 is mounted on the jack shaft. These gears have a two to fast as the main shaft. The jack shaft projects through the sideof the standard and-an eccentric 3G is mounted on the extended end of the shaft. An eccentric strap 36a surrounding the eccentric is held inplace by collars'3l on the shaft, one on each side of the eccentric. The eccentric strap is secured to -one end of a connecting rod 38 the other end of which is pivotally secured to the end of a lever 39 secured to the sleeve 30. Thus, the-sleeve 30' and the disk 26 are oscillated in a two to one relation with the needle, the eccentric being arranged to move-the disk 25 into effective, node-forming position on alternate strokes of the needle. The disk moves to the effective position with the feeding action of the material operated upon, while the needle is withdrawn; It will be apparent, of course, that the ratio of the movement of the disk 26 with respect to the needle may be other than two to one, as, for example, three to one depending upon the ratio of gears 34 and 35.

In Figs. 6 and 7 the relation of the disks 25 elements or disk-sectors 25 and 26. The disk 25 of reduced thickness shaped, in cross section, to

form an angle. This section 2611 of'the disk 26 overlies the edge of the disk 25. The disk 26, is mounted and secured on the end of a sleeve .30 rotatably mounted on the shaft 21.

The shaft 21 is oscillated to move the disk l 25 from an effective position in which it projects tions. In Figs. 5 and 6 the disk 25 is illustrated as inthe effectiveposition and the disk 26in an ineffective position. Fig. '7 illustrates the disk 26 in the effectiveposition.

The depth of penetration of the needle through the material operated upon is determined. by the relation of the periphery of the disks to the needle in their effective or node-forming position. Since the disk 26 overlies the disk 25, the needle I will penetrate the material operated upon deeper when the disk 26 is in the effective position than when the disk 25 projects the node of material into the path 'of the needle; Thus, when a hemming operation is performed on a dress bottom, the work table is set such that the disk 26 projects the edge of the hem and a node of the base layer of the material into th'e path of the needle and the needle penetrates both the base layer and the hem. When the machine is so adjusted and operated, the node formed by the disk 25 is insuflicient for the needle to penetrate the base layer but it does penetrate the hem. Thus, stitching known as skip-stitch is effected, the needle penetrating the base layer and the hem on one stroke and only the hem on the succeeding stroke.

In Fig. 8, there is disclosed a modified form of the operating mechanism for the node-forming disks. With this mechanism both the shaft 21 and the sleeve 39 are oscillated in a two to one relation with the needle. Both the shaft 21 and the sleeve 30 are driven from the jack shaft 33. Mounted on the jack shaft within the standard 3, there are two eccentrics 4|] and 4| angularly displaced one hundred and eighty degrees. An eccentric strap 42a: forming a part of a lever 42 at one end thereof surrounds the eccentric 40 and the lever is pivotally connected at its other end to a lever 43 connected to the sleeve 30. The eccentric 4| is surrounded by an eccentric strap 44a formed on one end of a lever 44. The other end of the lever is pivotally connected to the end of a lever 55 which is connected to the shaft 21. In this construction it will be apparent that the disks 25 and 26 move in opposite directions, one being in the eiTective position when the other is in the inefiective position, each disk coming into effective position every second stroke of the needle.

It will be observed that in each of the modifications illustrated the disks are relatively movable and move at different velocities, the term velocity signifying both speed and direction. In the form of the machine illustrated in Figs, 1 to 7, the two disks operate at different speeds and at times in different directions. In the modified form the disks operate in different directions.

It will be obvious that various changes may be made by those skilled in the art in the details of the embodiments illustrated in the drawings and described in detail above within the principle and scope of the invention as expressed in the appended claims.

I claim:

1. In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle, and node-forming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two node-forming elements relatively movable with respect to each other and mounted to move towards and away from the path of the needle, and means interconnecting the needle actuating means and. said node-forming elements for effecting relative movement between the node-forming elements to render said nodeforming elements independently effective at different strokes of the needle.

2. In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle, and node-forming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two node-forming elements relatively movable with respect to each other and each operative to move from an ineffective position to a position forming a node of material in the path of the needle, and means interconnecting the needle actuating means and said nodeforming elements for positively and continuously effecting relative movement between said nodeforming elements to render them independently effective, at different strokes of the needle.

3. In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle, and node-forming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two relatively movable node-forming elements, each operative to move from an ineifective position to a postion forming a node of the material operated upon in the path of the needle, and means interconnecting the needle actuating means and said node-forming elements for operating said node-forming elements at different velocities in timed relation with the movements of the needle.

4. In a sewing machine of the typo described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presesr foot, means for actuating the needle, and node-forming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two node-forming elements relatively movable with respect to each other and each operative to move from an inefiective position to a position projecting a node of the material operated upon into the path of the needle, and means interconnecting the needle actuating means and said node-forming elements for effecting relative movement between the nodeforming elements to render said node-forming elements successively eiiective to project a node of the material operated upon through the opening in the presser foot.

5. In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle, and nodeforming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two node-forming elements relatively movable with respect to each other and each operative to move from an ineffective position to an eifective position projecting a node of the material operated upon into the path of the needle, said nodeforming elements being arranged to project the material to different positions to vary the depth of penetration of the needle, and means interconnecting the needle actuating means and said node-forming movement between the node-forming elements to render said node-forming elements independently effective at different strokes of the needle.

6. In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle, and nodeforming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two node-forming elements relatively movable with respect to each other and each operative to move from an inefiective position to an effective position projecting a node of the material into the path of the needle, and means interconnecting the needle actuating means and said node-formelements for effecting relative ing elements for efiecting relative movement between the node-forming elements to render said node-forming element's independently and successively eliective in a two to one relation with respect to the reciprocations of the needle.

'7. In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle and nodeiorming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two relatively movable node-forming elements, each operative to move from an ineiiective position to an effective position projecting a node of material into the path of the needle and one of said node-forming elements being arranged to overlie the other, and means interconnecting the needle actuating means and said node-forming elements for rendering said node-forming elements independently and successively effective in a two to one relation with respect to the reciprocations of the needle.

8, In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle, and nodeforniing mechanism for projecting the material operated upon through the opening in the presser foot and into" the path of the needle including two angul'arly movable disk-like node-forming elements, each operative to move from an inefiective position to an effective position projecting a node of material into the path of the needle, and means interconnecting said needle actuating means and said node-forming elements for effecting relative movement between the node-forming elements to render the node-forming elements succssively effective.

9. In a sewing machine of the type described, the combination comprising a presser foot having an opening therethrough, a needle mounted for movement across the opening through the presser foot, means for actuating the needle, and nodelorming mechanism for projecting the material operated upon through the opening in the presser foot and into the path of the needle including two angularly movable disk-like node-forming elements, each operative to move from an inefiect-ive position to an effective position projecting a node of material into the path of the needle and one of said node-forming elements being arranged to overlie the other, and means interconnecting the needle actuating means and the node-forming means for rendering said node-forming elements independently effective on different strokes of the needle.

GEOFFREY STEVENSON. 

